Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnly/no-destructive/idempotent/no-open-world, but the description adds real behavioral context: no network fetch occurs, the emitted file omits a User-agent: * group, and each group cites the vendor page. It never explains the tension between the verb "Write" and readOnlyHint (no external state is mutated), which is the one thing left implicit.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Purpose is front-loaded and there is little filler, but the text is a chain of clipped fragments ("effect request_only means the vendor does not say the crawler obeys that line.", "control_token is not training.") that are hard to parse without prior domain knowledge. It is terse rather than well-structured.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a no-output-schema tool with four optional params and solid annotations, the description covers output shape (no wildcard group, cited vendor pages), side effects (no fetching), and misuse constraints. It is slightly short on how `policy` interacts with `allow`/`block` when both are supplied.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the baseline is 3. The description does add a little meaning ("control_token is not training", the negative list of fields not to send), but its "effect request_only" terminology does not match any enum value (the enum has owner_requested), which adds confusion rather than clarity.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

Names a specific verb and resource ("Write a robots.txt") plus the scope ("for the kinds you allow or block") and the distinguishing output trait (cited groups). An agent can tell this apart from check_robots/list_crawlers without opening a schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The intended use is implied by the purpose statement, and the closing sentence gives a negative constraint ("Do not send url, host, target, website, robots_url, or fetch"). However, it never says when to choose this over check_robots or what prerequisite data ("this dataset") must exist first.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.